Biradicals/Zwitterions from Thermolysis of Enyne−Isocyanates. Application to the Synthesis of 2(1<i>H</i>)-Pyridones, Benzofuro[3,2-<i>c</i>]pyridin-1(2<i>H</i>)-ones, 2,5-Dihydro-1<i>H</i>-pyrido[4,3-<i>b</i>]indol-1-ones, and Related Compounds
作者:Hongbin Li、Hua Yang、Jeffrey L. Petersen、Kung K. Wang
DOI:10.1021/jo049716t
日期:2004.6.1
leading to benzofuro[3,2-c]quinolin-6(5H)-one (20), 5,11-dihydro-11-methyl-6H-indolo[3,2-c]quinolin-6-one (25), benzofuro[3,2-c]pyridin-1(2H)-one 44, 2,5-dihydro-2,5-dimethyl-1H-pyrido[4,3-b]indol-1-one 46, and related compounds. Interestingly, thermolysis of 37f bearing a 2-(methoxymethyl)phenyl substituent at the alkynyl terminus produced the unexpected benzopyranopyridine 56 as the major product in a process
苯甲环化的烯炔异氰酸酯13和烯炔异氰酸酯36和37的热分解促进了环芳构化反应,从而分别在原位生成O,4-二氢-2-羟基喹啉和O,4-二氢-2-羟基吡啶作为反应中间体。这些环芳基化的中间体可被捕获为双自由基和/或两性离子,这取决于炔基末端的取代基的性质。可以将带有苯基取代基的13a环芳构化衍生的中间体视为双自由基14,然后从γ-萜品烯中提取氢原子,生成2(1 H)-喹啉酮15。或者,同一中间体也可被视为两性离子14 ',然后将其从γ-萜品烯中提取氢化物,然后进行质子化反应生成15。的存在下,2-苯乙基取代基在13B和37A或在2-甲基取代基37B也允许所得到的中间体的分子内或者被捕捉为双自由基或作为两性离子,制备2-(1 ħ) -喹啉酮19,2(1个ħ)-吡啶酮39和苯并吡喃吡啶43, 分别。另一方面,对于2-甲氧基苯基,2-(二甲基氨基)苯基或3-甲氧基丙基取代基,可以用两性离子中间体生成